1. Field of the Invention
The invention relates generally to emergency vehicle lighting and more particularly to systems for providing both emergency signal lighting and visual messaging capabilities to emergency vehicles.
2. Related Art
Emergency vehicles such as police cars and fire trucks often have emergency signaling systems mounted on them. Typically, these systems include emergency signaling lights that may flash in various colors and patterns, as well as sirens or public address loudspeakers. These devices enable emergency services personnel such as police officers or firefighters to warn people in the vicinity of the emergency vehicles that the vehicles are approaching or that there is a dangerous situation which is being handled by the emergency services personnel.
Many different types of emergency signaling systems exist. Typically, these systems are mounted on a bar or similar structure on the roof of the emergency vehicle. Consequently, these systems are often referred to as “light bars.” Many different types and configurations of emergency signaling lights, sirens and loudspeakers have been developed. These systems can facilitate such activities as stopping violators, establishing a “right of way”, or warning vehicles of road hazards. The traditional lights when activated can be viewed from the front, rear or sides and mostly are the same, front and rear, with the exception of light colors. Sirens and loudspeakers are typically mounted in or behind the front grill of the vehicle.
Although emergency vehicles such as police cars carry light bars to make them more visible in an emergency situation, there are times when it is desirable for these vehicles to be less noticeable. Traditional light bars on emergency vehicles are typically mounted across the entire top of the vehicle, which makes them more visible and results in an easily recognizable profile. This can provide an unwanted identification of the vehicle as a law enforcement vehicle when it approaches other vehicles. For instance, if a police officer wishes to approach a speeding car to confirm that it is exceeding the posted speed limit, it may be desirable for the police vehicle to be less easily identifiable until the police officer decides to pull over the speeding car. Then, it would be beneficial for the police vehicle to be more visible and identifiable so that the speeding car would be aware of the police vehicle and the need to pull over.
More advanced light bar systems contain banks of LEDs (light emitting diodes) which may be positioned two or more rows high and may therefore be used to design a low-profile light bar. These low-profile light bars may be mounted on the top of an emergency vehicle, on the front of the vehicle above or near the top of the windshield, or inside the vehicle near the top of the windshield. The profiles of these light bars are lower than traditional light bars but, if mounted outside the vehicle, are still recognizable as described above. Light bars mounted either near the top of the windshield or inside the windshield suffer from the undesired effect of blocking part of the occupants' view through windshield. This may make it difficult to see traffic lights and other signs from inside the vehicle. Similarly, light bars mounted on the inside of the rear window of an emergency vehicle can block the view through the window and may therefore hinder safe operation of the vehicle.
Another method which is currently used to make emergency vehicles more stealthy is to replace existing headlights and directional lights with colored warning lights and/or to mount warning lights in the grill area on the front of the vehicle and on the rear of the vehicle. However, these warning lights are generally less visible and therefore less effective than lights which are mounted on the roof of the vehicle. These warning lights are also typically expensive to install and expensive to replace when the vehicle is put out of service. Further, when the warning lights are installed in place of the headlamps or directional signal lights, they negate the function of those lights.
Conventional emergency vehicle light bars also typically provide no means for the emergency vehicles to communicate the specific nature of a traffic warning or road hazard, but can only slow down traffic by flashing the emergency lights. This may cause problems, as some drivers may panic and brake too quickly or pay more attention to the lights and/or road hazard than to other vehicles. This may cause result in accidents or additional traffic congestion. While stand-alone message signs for traffic control and/or hazard warning are available, these signs are either stationary or movable only by towing them into position. This takes time, so the signs are not usually in place until long after the emergency vehicle arrives at the scene of the accident or hazard. In most cases, these signs are not used at all because of their inconvenience.
Smaller message display units may be positioned in the interior of an emergency vehicle in the rear window. These small displays are mainly used in private vehicles to display courtesy messages and are designed to be viewed from a short distance behind the vehicles. These message units are not suitable for use in an emergency situation to warn drivers of road hazards and other warning messages because they are not visible from a long distance and therefore do not allow drivers of other vehicles to take action as directed by the message on the display. Also, they typically block a substantial portion of the view through the vehicle's rear window and may therefore hinder the safe operation of the vehicle.
There is also a class of vehicle displays which are oriented toward advertising. These displays are designed to be viewable to pedestrians and other vehicles primarily from the sides of the vehicle carrying the display. Also, since these displays are intended to be highly visible, they are not designed to have a low profile or to be stealthy or hidden when not in use. Further, these advertising-oriented displays are typically designed to display a single predetermined message or a series of rotating messages which may not be programmed from within the vehicle.
There are many examples of the systems that are available in the prior art. For example, U.S. Pat. No. 6,461,008 to Pederson illustrates a light bar having a typical roof-mounted configuration, but this system does not have a message display and is not movable. German Patent Applications 3,807,684 and 4,001,302 provide examples of roof-mounted light bars that incorporate message displays, but these systems are not movable. U.S. Pat. Nos. 4,928,084 and 5,825,281 illustrate window-mounted displays, but these displays do not incorporate emergency signal lights and are not movable. German Patent Applications 3,533,588 and 3,631,578 and Japanese Patent Application 60050049 show signs that can be folded down, but these signs do not incorporate emergency signal lights and are not programmable with different messages. German Patent Application 20310472U illustrates a light bar that has a message display, but only the message display folds down, and the message display is not programmable. U.S. Pat. No. 7,262,707 shows a light bar with a message display that incorporates flashing lights, but the light bar is not movable. Finally, U.S. Pat. Nos. 3,761,890 and 4,081,788 are examples of emergency lights and message displays that are movable, but neither of these systems has programmable displays and neither can be aerodynamically positioned.
As explained above, existing light bars and vehicle displays do not allow emergency vehicles to have the combined capabilities of selective stealth, aerodynamic and high visibility positions, as well as combined emergency signal lights and programmable message or graphics displays. It would therefore be desirable to provide emergency signaling/messaging systems that provide these capabilities and other capabilities as described below.